Optical data signals in free space optical communication systems are typically modulated by out-of-band beacon tones to allow mechanical systems to properly align the free space optical transceivers. Typically, only a single data signal level (the “high” data signal level) is modulated with the beacon tone. However, the beacon tone may be difficult to filter out thereby limiting the usefulness of the data signal. Accordingly, there is a need for better modulating techniques for transmitting optical data signals.